Lithium batteries are widely used in notebook computers, mobile phones, digital cameras, video cameras, personal digital assistants (PDAs), Bluetooth headsets, and wireless 3C products.
A negative electrode material of conventional commercial lithium batteries mainly includes a carbon material, such as mesocarbon microbeads (MCMBs) having a capacity of 310 mAh/g and artificial graphite having a capacity of 350 mAh/g. However, the negative electrode material with carbon as the main body has a bottleneck of theoretical capacity of 372 mAh/g, which cannot meet the requirement of high-power and high-energy density lithium batteries in the future.
Based on the above, high-capacity negative electrode material is a critical material of the high-energy lithium batteries. Researchers set forth that high gravimetric capacity (3,800 mAh/g) can be obtained by using a silica-based negative electrode material. However, the silica-based negative electrode material has a characteristic of high irreversible capacity, and may have a volume expansion of 400% after charge.
Specifically, during charge and discharge of the lithium battery, as the lithium ion intercalates/deintercalates the silica-based negative electrode material, material expansion and contraction occur on the silica-based negative electrode material, such that the silica-based negative electrode material is fractured, and the internal impedance is increased, thus reducing the usability of the lithium battery.